add HSP IAM audit capabilities

[EriksonBahr]

Description

Add HSDP IAM audit capabilities to oauth2 proxy

Motivation and Context

HSDP IAM does not provide important audit capabilities out of the box such as successful login and some key auth errors.

How Has This Been Tested?

Tested locally with:

export OAUTH2_PROXY_ENABLE_AUDIT='true'
export OAUTH2_PROXY_AUDIT_URL='url'
export OAUTH2_PROXY_AUDIT_PRODUCT_NAME='Reporting'
export OAUTH2_PROXY_AUDIT_PRODUCT_KEY='product key'
export OAUTH2_PROXY_AUDIT_SHARED_KEY='shared key'
export OAUTH2_PROXY_AUDIT_SECRET_KEY='secret'

Example of the payload:

{
  "resourceType": "AuditEvent",
  "event": {
    "type": {
      "system": "http://hl7.org/fhir/ValueSet/audit-event-type",
      "version": "1",
      "code": "110114",
      "display": "User Authentication"
    },
    "action": "E",
    "dateTime": "2024-07-03T16:34:44Z",
    "outcome": "0",
    "outcomeDesc": "Success"
  },
  "participant": [
    {
      "userId": { "value": "[email protected]" },
      "altId": "admin_t952",
      "requestor": true
    }
  ],
  "source": {
    "identifier": {
      "type": {
        "system": "http://hl7.org/fhir/ValueSet/audit-source-type",
        "code": "4",
        "display": "Application Server"
      },
      "value": "[email protected]"
    },
    "type": [
      {
        "system": "http://hl7.org/fhir/security-source-type",
        "code": "1",
        "display": "End-user display device, diagnostic device."
      }
    ],
    "extension": [
      {
        "url": "/pics/reporting?procedure.identifier=https%3A%2F%2Fwww.philips.com%2Fidentifiers%2FProcedureIdentifier|ACC_20240625221043040",
        "extension": [
          { "url": "applicationName", "valueString": "Reporting" },
          { "url": "applicationVersion", "valueString": "1" },
          { "url": "serverName", "valueString": "oauth2proxy" },
          { "url": "componentName", "valueString": "oauth2proxy" },
          {
            "url": "productKey",
            "valueString": "<omited>"
          },
          {
            "url": "tenant",
            "valueString": "3b64ff86-8ecf-47cb-8431-bedf41318e43"
          }
        ]
      }
    ]
  }
}

Checklist:

• My change requires a change to the documentation or CHANGELOG.
• I have updated the documentation/CHANGELOG accordingly.
• I have created a feature (non-master) branch for my PR.

[evozniak]

Minor comments, looking good.